A US man is in critical condition after surgeons removed an unexploded firework from his chest.

Anoka County Sheriff's Detective Mike Lapham says 31-year-old Nick Beheng was launching fireworks from a hand-held mortar tube Saturday when one misfired. Lapham says the firework blew out of the bottom of the tube, directly into the 31-year-old man's chest.

Beheng was rushed to Minnesota's St Paul's Regions Hospital where surgeons summoned the police bomb squad. Police Sergeant Paul Paulos says the bomb squad stood by in the waiting room as the explosive was removed, then took it to a bunker at their training facility in Rosemount.

Paulos says the firework is about the size of an empty paper towel tube and is capable of shooting well over 100 metres in the air.